A general partial discharge detecting device for a power transformer is disposed within electric power equipment while maintaining a predetermined insulating distance, and detects partially discharged signals.
When the partial discharge detecting device is disposed within a drain valve of the power transformer, the partial discharge detecting device does not additionally include a separate inspection window, and sensors can be arranged at various locations.
FIG. 1 illustrates a partial discharge detecting device according to the related art.
Referring to FIG. 1, a partial discharge detecting device according to the related art is disposed within a drain valve.
The partial discharge detecting device 10 is separately provided with a signal input end 11 and a signal output end 13. The partial discharge detecting device 10 detects partially discharged signals with receiving units 12a and 12b, in which the receiving units 12a and 12b are connected to the input end and the output end, respectively, in the form of a parallel coupler.
Although a frequency band of signals generated during partial discharge corresponds to a wideband, the partial discharge detecting device generally detects signals in the frequency band of 0.3 to 1.5 GHz of the Ultra High Frequency (UHF) band (0.3˜3 GHz) less affected by noise. In order to receive signals of the wide UHF band, wideband properties are required. It is impossible to have a wideband through a single shape and an identical shape since a wavelength is physically restricted, and therefore, it is necessary to design a receiving unit having several wavelengths.